Polypedilum

Saether, Ole A., Andersen, Trond, Pinho, Luiz C. & Mendes, Humberto F., 2010, The problems with Polypedilum Kieffer (Diptera: Chironomidae), with the description of Probolum subgen. n., Zootaxa 2497, pp. 1-36 : 11-12

Polypedilum subgenus Polypedilum Kieffer

Polypedilum Kieffer, 1913: 15 ; not Kieffer (1912: 41). Kribiocharis Kieffer, 1922: 1 .

Pentapelma Kieffer, 1921b: 98 ; 1921c: 33.

Rosenia Kieffer, 1921a: 275 ; not Waagen and Wentzel (1887: 943). Propedilum Lenz, 1937: 13 .

Type species

Polypedilum (Polypedilum) nubeculosum (Meigen) Chironomus nubeculosus Meigen, 1804: 18 . Polypedilum emarginatum Kieffer, 1913: 16 .

The genus Polypedilum Kieffer was described in 1913 and Polypedilum emarginatum Kieffer, 1913 [= P. nubeculosum (Meigen, 1818) ] designated as the type of the genus ( Kieffer 1913: 15). As shown by Ashe (1981), however, the type designation was invalid as two species were assigned to the genus Polypedilum in a paper published a year earlier ( Kieffer 1912: 41). Of the two species, P. pelostolum Kieffer, 1912 and P. ceylanicum ( Kieffer, 1912) , at least the first according to Freeman (1961) is a synonym of P. nubifer and was selected as the type species. However, Freeman (1961) stated that P. nubifer is without frontal tubercles, while the presence of frontal tubercles is one of the most significant features of the species. Two syntypes of P. pelostolum from The Natural History Museum in London were examined. The specimens were lacking wings, antennae, hypopygia and most legs, but one head with frontal tubercles intact remained. Accordingly the synonymy with P. nubifer has to be accepted. As shown here P. nubifer , however, should be placed in Tripedilum . A case will be made to ICZN for rejecting the type designation of Ashe (1981) and maintaining the type designation of Kieffer (1913).

Diagnostic characters. The male imagines of the subgenus can be distinguished by having no frontal tubercles, bare wing membrane, wing vein R2+3 usually relatively well separated from R1, projection of superior volsella long compared to the short base and nearly always with outer seta and anal point never trifid or with lateral teeth or shoulders to each side of the anal point.

The few female imagines sufficiently described have nearly straight spermathecal ducts and the dorsomesal lobes of gonapophysis VIII are not reaching much caudal of the ventrolateral lobes.

The pupa has no frontal tubercles and no or vestigial cephalic tubercles, less than 20 branches in thoracic horn, single spur on caudolateral margin of segment VIII, taeniae on segments V and VI may be reduced in size or number and anal lobe without dorsal setae.

The larva has opposing Lauterborn organs; third antennal segment distinctly longer to somewhat shorter than fourth; pecten epipharyngis occasionally with less than 3 teeth in median scale, usually 3–5; mandible occasionally without dorsal tooth, usually with; occasionally mola smooth, usually serrate; mentum usually with first lateral teeth distinctly lower than second and median teeth, but often at least as high as median and/ or second lateral teeth; and ventromental plates without posterior lobes, with median apices pointing towards each other and distance between plates usually at least as long as combined width of 4 median teeth.

Remarks. The pupae of Polypedilum s. str. are not separable from those of Pentapedilum , Uresipedilum and Probolum. Most larvae cannot be distinguished from those of Pentapedilum . Some larvae, however, are separable from other known larvae except P. (Pe.) epleri Oyewo et Jacobsen, 2007 , by having first lateral teeth of mentum at least as high as median and/or second lateral teeth. From P. (Pe.) epleri they differ by either having mandible with a dorsal tooth, mola without serrations or well developed Lauterborn organs.